She was told by staff - stationed out the front of school - that a former student has sent an email threatening the school.
Staff are standing outside telling their parents to take their children home.
Police have also been sent to the school, board chairman Mark Junge said.
He said a threat had been made to the school, via email or voice mail, at some stage overnight.
"The responsible thing is to close the school until police have been through their process and then there will be more information."
Mr Junge says police have been and gone from the school and are currently following up leads.
School principal Phil Missen says they believe the threat might be fake but they are treating it seriously until police have finished their investigation.
While they wouldn't confirm what the threat was, for fear of copycats, Mr Missen says it was a threat with a "timeframe around it".